1. Field of the Invention
This invention relates to a method of agglomerating coal particles with hydrocarbon oil, and more particularly to a method for reducing the amount of hydrocarbon oil required to form coal-hydrocarbon oil agglomerates.
2. Prior Art
Heretofore, it was known that coal particles could be agglomerated with hydrocarbon oils. For example, U.S. Pat. No. 3,856,668 to Shubert issued Dec. 24, 1974, and U.S. Pat. No. 3,665,066 to Capes et al issued May 25, 1972 disclose processes for recovering coal fines by agglomerating the fine coal particles with oil. U.S. Pat. No. 3,268,071 to Puddington et al issued Aug. 23, 1966 and U.S. Pat. No. 4,033,729 issued July 5, 1977 to Capes disclose processes for beneficiating coal involving agglomerating coal particles with oil in order to provide a separation of coal from ash. While these processes can provide some beneficiation of coal, improved ash and pyritic sulfur removals would be desirable.
The above U.S. Pat. No. 4,033,729 to Capes et al relating to removing inorganic materials (ash) from coal significantly notes that pyritic sulfur has proven difficult to remove because of its possible hydrophobic character. This disclosure confirms a long standing problem. The article "The Use of Oil in Cleaning Coal" Chemical and Metallurgical Engineering, Vol. 25, pages 182-188 (1921) discusses in detail cleaning coal by separating ash from coal in a process involving agitating coal-oil-water mixtures, but notes that pyrite is not readily removed in such a process. In such a process, beneficiation of coal would be greatly improved if pyrite sulfur removal could be enhanced.
While it is known that hydrocarbon oil agglomeration can be useful in recovering coal particles and/or beneficiating coal, the large amount of hydrocarbon oil required in these prior art coal agglomeration processes has detracted from their usefulness. It would be especially advantageous if the amount of hydrocarbon oil could be reduced in forming hydrocarbon oil coal agglomerates.